(a) Field of the Invention
The present invention relates to an automatic defogging system of a vehicle and a control method thereof. In particular, the present invention provides automatic defogging system of a vehicle and a control method thereof automatically removing fog or frost on an inner surface of a window while maintaining comfortable conditions inside the vehicle.
(b) Description of the Related Art
An air conditioning system makes comfortable conditions for occupants in a vehicle by removing fog or frost on the window. An air conditioning system includes an air ventilation device, an air conditioner, and a defrost switch included in the air conditioner.
The air ventilation device is divided into a spontaneous ventilation type which brings in air from the outside and sends the outer air into the vehicle by a pressure difference generated by vehicle driving and a compulsory ventilation type using a blower. The air conditioner adopts the compulsory ventilation type.
It is configured such that the hot air flows downward and the cold air flows upward or moves along a surface of a window from an outlet in order to removing fog on an inner surface of a window. The occupant can regulate air flow within the vehicle by controlling the opening and closing of a duct.
The duct controls operations of respective elements constituting an air conditioning system. The duct is controlled by switches located in an instrument panel such as a blower switch, a mode switch, and a heating/cooling switch.
By controlling the air conditioning system, the conditions in the vehicle are comfortable. In particular, the defrost switch is a device that removes humidity, fog or frost on a window. In particular, humidity, fog or frost can be removed thereby securing a view of an occupant.
An air conditioning system removes concentrated humidity or prevents the concentration of humidity, as shown in FIG. 1. FIG. 1 includes an input unit 1 which sends out electrical signals from a window surface temperature sensor which detects the temperature of the surface of a window and an interior humidity sensor detects the humidity in a vehicle; a controller 2 which includes an air conditioning system that is programmed to a specific logic and selectively and phasedly is controlled based on a difference between a window surface temperature value detected by the window surface temperature sensor and a dew-point temperature calculated by the detected value of the interior humidity sensor, and an output unit 3 that is a selection mode of an air conditioning system that can be controlled by the controller 2. In this application, “sensed” and “detected” are used interchangeably. Additionally, a control unit comprises a processor, a memory, and associated hardware and software as may be selected and programmed by persons of ordinary skill in the art based on the teachings of the present invention contained herein.
By operating an air cooling function or an air heating function according to the weather, the concentrated humidity on a window can be automatically removed or the concentration of humidity can be prevented.
However, since the humidity of the window is estimated by the temperature value detected by the window surface temperature and an interior humidity value detected by the interior humidity sensor, an accurate humidity value cannot be obtained.
In addition, since the defrost door cannot be independently controlled, a temperature change inside the vehicle may occur.
If a driver uses the control logic of the conventional air conditioning system, a driver may feel alienation according to a mode operation, and it is quite difficult to maintain a room temperature.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.